#!/usr/bin/env node

const mysql=require('mysql2/promise'),
      log=console.log;

let con =mysql.createPool({
  host:'127.0.0.1',
  user:'root',
  password:'ddd',
  database:'test'
});

async function addAreas(areaName){
  const sql="insert into areas(area_name) values('${areaName}')";

  let [rows]=await con.execute(sql);
  return rows;

}

async function delAreas(areaName){
  const sql="delete from areas where area_name = '${areaName}'";

  let [rows]=await con.execute(sql);
  return rows;

}


async function updateAreas(oldName,newName){
  const sql="update areas set areas_name = '${newName}' where area_name='${oldName}'";

  let [rows]=await con.execute(sql);
  return rows;

}


async function getAreas(){
  const sql='select * from areas';

  let [rows]=await con.execute(sql);
  return rows;
}

(async function(){
  //await addAreas('英国');
  //await updateAreas('英国','大不列颠');
  await delAreas('大不列颠');
  log(await getAreas());
})();
